Preparation of acrylic or methacrylic acid from acrolein or methacrolein

ABSTRACT

Methacrylic acid or acrylic acid are produced by the oxidation of methacrolein or acrolein, respectively, with molecular oxygen in the vapor phase in the presence of a catalytic oxide of molybdenum, phosphorus, bismuth, copper, oxygen, optionally a halogen selected from the group consisting of chlorine, bromine or iodine, and optionally, at least one element selected from the group consisting of Fe, Cr, Ni, Mn, Sb, Te, Rh, and Pd.

REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of our earlier application, U.S. Ser. No.701,259, filed June 30, 1976, now abandoned.

BACKGROUND OF THE INVENTION

A number of catalysts are known to be effective for the oxidation ofacrolein or methacrolein to acrylic acid or methacrylic acid,respectively. However, the yields obtained using the catalysts for thepreparation of methacrylic acid are low. The present invention is aresult of a search for more efficient and desirable catalysts for theproduction of acrylic acid and methacrylic acid. Unexpected higheryields of and selectivities to acrylic acid and methacrylic acid areobtained by the vapor phase oxidation of acrolein and methacrolein,respectively, with molecular oxygen in the presence of the new anduseful catalysts of the present invention.

SUMMARY OF THE INVENTION

It has been discovered according to the present invention in the processfor the preparation of acrylic acid or methacrylic acid by the oxidationof acrolein or methacrolein, respectively, with molecular oxygen in thevapor phase at a reaction temperature of about 200° C. to about 500° C.in the presence of an oxide catalyst, and optionally in the presence ofsteam, the improvement comprising using as a catalyst a catalyst of theformula

    Mo.sub.12 P.sub.a Bi.sub.b Cu.sub.c M.sub.d X.sub.e O.sub.f

wherein M is at least one element selected from the group consisting ofiron, chromium, nickel, manganese, tellurium, palladium, antimony, andrhodium;

X is a halogen selected from the group consisting of chlorine, bromine,or iodine;

AND WHEREIN A, B, AND C ARE NUMBERS FROM 0.001 TO 10;

D IS FROM 0 TO 10;

E IS 0 TO 5;

F IS A POSITIVE NUMBER OF OXYGENS REQUIRED TO SATISFY THE VALENCE STATESOF THE OTHER ELEMENTS PRESENT.

The surprisingly advantageous catalysts of this invention give improvedyields of acrylic acid and methacrylic acid from acrolein andmethacrolein, respectively, in an efficient, convenient, and economicalmanner at a relatively low temperature. The exotherm of the reaction islow, thereby allowing easy reaction control.

The most significant aspect of the present invention is the catalystemployed. The catalyst may be any of the catalysts delineated by theabove formula. The catalysts can be prepared by a number of differenttechniques described in the art, such as coprecipitation of solublesalts and calcination of the resulting product.

The catalysts of the invention have preferred limitations on theircomposition. Preferred are catalysts wherein a, b, and c are numbersfrom 0.01 to 5 and e is from 0 to 1.0. Also preferred are catalystswherein a is 1 to 1.5, catalysts wherein b is 0.1 to 0.5, catalystswherein c is 0.1 to 1.0, and catalysts wherein e is 0.01 to 0.5.Especially preferred are catalysts wherein e is 0.01 to 0.20, andcatalysts wherein d is zero. Especially preferred are catalysts whereinX is chlorine. Catalysts of special interest are described whereinchlorine, bromine, or iodine is present as an essential catalyticcomponent. Especially preferred are catalysts wherein chlorine is arequired component.

In the catalyst preparations, the various elements of the catalyst arecombined, and the final product is calcined to obtain the catalyst. Anumber of methods of combining the elements of the catalyst andcalcining the resultant product are known to those of skill in the art.In the broad concept of the invention, the particular method ofpreparing the catalysts is not critical.

There are, however, methods of preparing the catalysts that have beenfound to be preferred. One preferred preparation involves thepreparation of the catalysts in an aqueous slurry or solution ofmolybdenum and/or phosphorus containing components, and adding theremaining components; evaporation of this aqueous mixture; andcalcination of the resulting catalysts. Suitable molybdenum compoundsthat may be employed in the preparation of the catalysts delineated bythe above formula include molybdenum trioxide, phosphomolybdic acid,molybdic acid, ammonium heptamolybdate and the like. Suitable phosphoruscompounds that may be employed in the preparation of the catalystsinclude ortho phosphoric acid, metaphosphoric acid, triphosphoric acid,phosphorous pentabromide, phosphorus pentachloride, and the like. Theremaining components of the catalysts may be added as oxide, acetate,formate, sulfate, nitrate, carbonate, oxyhalide, or halide and the like.

The catalysts of this invention also may be prepared by mixing thecatalytic components in an aqueous slurry or solution, heating theaqueous mixture to dryness and calcining the resulting catalysts.

Excellent results are obtained by refluxing phosphoric acid andmolybdenum trioxide in water for about 1.5 to 3 hours, however,commercial phosphomolybdic acid may be effectively utilized; adding theremaining components to the aqueous slurry and boiling to a thick paste,where at least one of the components is added as a halide or oxyhalide;drying at 110° to 120° C. in air; and calcining the resulting catalysts.It is not clearly understood where the halogen atom is located in thecatalytic structure. Infra-red and X-ray analysis reveals that thecatalysts are mostly phosphomolybdate-based and that the halogen may bepresent as a molybdenum oxyhalide.

Excellent results are obtained using a coated catalyst consistingessentially of an inert support material having a diameter of at least20 microns and an outer surface, and a continuous coating of said activecatalyst on said inert support strongly adhering to the outer surface ofsaid support. The special coated catalyst consists of an inner supportmaterial having an outer surface and a coating of the active catalyticmaterial on this outer surface.

The support material for the catalyst forms the inner core of thecatalyst. This is an essentially inert support and may havesubstantially any particle size although a diameter of at least 20microns is preferred. Especially preferred in the present invention foruse in a commercial reactor are those supports which are spherical andwhich have a diameter of about 0.2 cm. to about 2 cm. Suitable examplesof essentially inert support materials include: Alundum, silica,alumina, alumina-silica, silicon carbide, titania and zirconia.Especially preferred among these supports are Alundum, silica, aluminaand alumina-silica.

The catalysts may contain essentially any proportion of support andcatalytically active material. The limits of this relationship are onlyset by the relative ability of the catalyst and support material toaccommodate each other. Preferred catalysts contain about 10 to about100 percent by weight of catalytically active material based on theweight of the support.

The preparation of these coated catalysts can be accomplished by varioustechniques. The basic method of preparing these catalysts is topartially wet the support material with a liquid. The support cannot bewet on the outside surface of the total mass. It should be dry to thetouch. If the support is wet, then the active catalytic material willagglomerate into separate aggregates when coating of the support isattempted. These partially wet supports are then contacted with a powderof the catalytically active material and the mixture is gently agitateduntil the catalyst is formed. The gentle agitation is most convenientlyconducted by placing the partially wet support in a rotating drum andadding the active catalytic material until none is taken up by thesupport. This is very economically done.

The calcination of the catalyst usually is accomplished by heating thedry catalytic components at a temperature of about 300° to about 700° C.For example, the catalyst can be calcined at 325°-450° C. in air. Theparticular calcination for the most desirable results varies as thedifferent catalysts are prepared. The best calcination conditions forcatalysts of the invention are shown in the Specific Embodiments.

The reactants of the reaction of the invention are methacrolein andoxygen. Molecular oxygen is normally supplied to the reaction in theform of air, but oxygen gas could also be employed. About 0.5 to about 4moles of oxygen are normally added per mole of methacrolein.

The reaction temperature may vary as different catalysts are employed.Normally, temperatures of about 200° to about 500° C. are employed withtemperatures of 250° to 370° C. being preferred.

The reaction is conveniently conducted in either a fixed-bed orfluid-bed reactor. The contact time may be as low as a fraction of asecond or as high as 20 seconds or more. The reaction may be conductedat atmospheric, superatmospheric or subatmospheric pressure, withabsolute pressures of about 0.5 to about 4 atmosphere being preferred.

When used in the reactor, the catalyst may be in a supported orunsupported form. Suitable support materials include, Alundum, silica,alumina, boron phosphate, zirconia, silicon carbide, or titania.

When the catalysts are reacted with acrolein or methacrolein in afixed-bed reactor, the active catalytic components may be coated on aninert support; however, in the alternative, the active catalyticingredients may be mixed with one of the above support materials priorto coating the inert support.

It is also contemplated by the present invention that acrolein ormethacrolein may be oxidized by the instant vapor phase catalyticreaction using the catalysts of the invention provided that a minorquantity of chlorine, iodine, or bromine or an inorganic or organichalide is incorporated in the feed.

Using the catalysts of the invention in the preparation of methacrylicacid or acrylic acid, excellent yields are obtained in a convenientreaction with low amounts of byproducts.

SPECIFIC EMBODIMENTS Examples 1 to 9

Various catalysts of the invention were prepared as follows:

EXAMPLE 1 Mo₁₂ P₁.32 Bi₀.5 Cu₀.25 Cl₀.06 O_(x)

Part A.

A slurry was prepared of 86.4 (0.06 mole Mo) of molybdenum trioxide and7.6 g. (0.067 mole P) of 85% phosphoric acid in 500 mls. of distilledwater; boiled with stirring for three hours to form phosphomolybdic acidwhich was yellowish green in color. To this slurry was added 2.5 g.(0.0125 mole Cu) of copper acetate; no change in color, followed by theaddition of 7.9 g. (0.025 mole Bi) of bismuth chloride dissolved in 4.0ml. of concentrated hydrochloric acid. The mixture was boiled todryness; dried overnight at 110° C. in air. The catalyst was ground andscreened to 20/30 mesh fraction and calcined for three hours at 400° C.in 40 ml/min. air.

Part B.

A large-size batch of this catalyst was prepared using 3500 mls.distilled water, 432 grams of molybdenum trioxide, 38 grams ofphosphoric acid, 12.5 grams of copper acetate, 39.5 grams of bismuthchloride dissolved in 25 mls. of concentrated hydrochloric acid. Themixture was heated overnight at 75° C. boiled to dryness; driedovernight at 110° C. in an oven; ground and screened; and calcined forthree hours at 400° C. in 40 ml/min air.

EXAMPLES 2 TO 9

These catalysts were calcined in the same manner described in Example 1.

EXAMPLE 2 Mo₁₂ P₁.32 Bi₀.5 Cu₀.25 Cl₀.04 O_(x)

This catalyst was prepared in the same manner as in Example 1, Part B.

EXAMPLE 3 Mo₁₂ P₁.32 Bi₀.5 Cu₀.25 Cl₀.05 O_(x)

This catalyst was prepared in the same manner as in Example 1, exceptthe molybdenum trioxide and phosphoric acid were replaced with 118.3 g.of commercially available phosphomolybdic acid and 1.84 g. of 85%phosphoric acid.

EXAMPLE 4 Mo₁₂ P₁.32 Bi₀.5 Cu₀.25 Cl₀.055 O_(x)

This catalyst was prepared in the same manner as in Example 1, exceptthat the hydrochloric acid was replaced with 15 mls. of concentratednitric acid.

EXAMPLE 5 Mo₁₂ P₁.32 Bi₀.5 Cu₀.25 Cl₀.06 O_(x)

This catalyst was prepared in the same manner as in Example 1, exceptthe bismuth chloride was replaced with 5.8 g. (.025 mole Bi) of bismuthoxide.

EXAMPLE 6 Mo₁₂ P₁.32 Bi₀.5 Cu₀.25 O_(x)

This catalyst was prepared in the same manner as in Example 1, except nohalogen was employed in the preparation. The bismuth chloride wasreplaced with 5.8 g. (.025 mole Bi) of bismuth oxide and hydrochloricacid was not employed in the preparation.

EXAMPLE 7 Mo₁₂ P₁.32 Bi₀.5 Cu₀.25 O_(x)

This catalyst was prepared in the same manner as in Example 6, exceptthe bismuth oxide was replaced with 12.1 g. of Bi(NO₃)₃.5H₂ O.

EXAMPLE 8 Mo₁₂ P₁.32 Cu₀.15 Bi₀.3 Fe₀.1 Cr₀.1 Ni₀.1 Cl₀.04 O_(x)

A slurry was prepared from 86.4 g. (0.60 mole Mo) molybdenum trioxideand 7.6 g. (0.067 mole P) of 85% phosphoric acid in 500 mls. ofdistilled water. To this slurry was added 1.5 g. (0.0075 moles Cu) ofcopper acetate, 4.8 g. (0.015 mole Bi) of bismuth chloride, 5.0 mls. ofconcentrated hydrochloric acid, 1.4 g. (0.005 mole Fe) of ferricchloride hydrate, 0.4 g. (0.005 mole Cr) of chromium oxide and 0.9 g.(0.005 mole Ni) of nickel acetate.

EXAMPLE 9 Mo₁₂ P₁.32 Cu₀.2 Bi₀.4 Sb₀.1 Ni₀.05 Cl₀.04 O_(x)

A slurry was prepared from 86.4 g. (0.60 mole Mo) of molybdenum trioxideand 7.6 g. (0.067 mole P) of 85% phosphoric acid in 500 mls. ofdistilled water and refluxed for 3 hours with heating; the color wasyellowish green.

To this slurry was added 0.7 g. (0.005 mole Sb) of antimony oxide; thecolor changed to dark green, and then was added 2.0 g. (0.01 mole Cu) ofcopper acetate, 6.3 g. (0.02 mole Bi) of bismuth chloride, 3.5 mls. ofconcentrated hydrochloric acid and 0.4 g. (0.0025 mole Ni) of nickelacetate.

EXAMPLES 10 to 18

Preparation of methacrylic acid using various catalysts of theinvention.

The catalysts were prepared in the same manner as shown above using theappropriate ratios of ingredients.

A portion of these catalyst particles were charged to a 20 cc. fixed-bedreactor consisting of a 1.3 cm. stainless steel tubing equipped with a0.3 cm. axial thermowell. The reactor was heated to reaction temperatureunder a flow of air and a feed of methacrolein/air/steam of 1/6.2/5.2and was fed over the catalyst at an apparent contact time of 4 to 5seconds. The reactor was run under the reaction conditions for 1 to 5hours and the product was collected and analyzed. The reactionconditions and results of the experiments are shown in TABLE I. Thefollowing definitions are used in measuring the carbon atoms in the feedand the products. ##EQU1##

                                      TABLE I                                     __________________________________________________________________________    PREPARATION OF METHACRYLIC ACID                                               USING VARIOUS CATALYSTS OF THE INVENTION                                                              Results, %                                                                    Single Pass                                                                          Single Pass                                                                          Selectivity  Catalyst                                     Reaction                                                                            Yield Meth-                                                                          Yield Acetic                                                                         Methacrylic                                                                          Total Preparation                Ex.                                                                              Catalyst       Temp.° C                                                                     Acrylic Acid                                                                         Acid   Acid   Conversion                                                                          Employed:                  __________________________________________________________________________    10 Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f                              316   69.4   3.5    79.5   87.3  BiCl.sub.3 + HCl           11 Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f                              313   70.4   6.6    74.6   94.5  BiCl.sub.3 + HCl                                                              (large batch size)         12 Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.05 O.sub.f                              302   63.9   5.8    73.0   87.6  Commercially                                                                  available                                                                     PMA + BiCl.sub.3 +                                                            HCl                        13 Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.055 O.sub.f                             337   40.3   7.9    61.1   65.9  BiCl.sub.3                                                                    + HNO.sub.3                14 Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f                              316   52.0   4.1    74.4   70.0  Bi.sub.2 O.sub.3 +                                                            HCl                        15 Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 O.sub.f                                          330   38.0   8.0    59.0   65.4  Bi.sub.2 O.sub.3 ; no                                                         halogen                    16 Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 O.sub.f                                          350   28.3   9.9    50.3   56.2  Bi(NO.sub.3).sub.3 .                                                          5H.sub.2 O                                                                    no halogen                 17 Mo.sub.12 P.sub.1.32 Cu.sub.0.15 Bi.sub.0.3 Fe.sub.0.1                                       330   61.9   3.8    76.7   80.7  BiCl.sub.3 + HCl               Cr.sub.0.1 Ni.sub.0.1 Cl.sub.0.04 O.sub.x                                 18 Mo.sub.12 P.sub.1.32 Cu.sub.0.20 Bi.sub.0.4 Sb.sub.0.1                                       313   64.9   4.4    79.5   81.6  BiCl.sub.3 + HCl               Ni.sub.0.05 Cl.sub.0.04 O.sub.f                                           __________________________________________________________________________

EXAMPLES 19 TO 21

Effect of reaction temperature and proper calcination of the catalystsin the preparation of methacrylic acid using the catalyst Mo₁₂ P₁.32Bi₀.5 Cu₀.25 Cl₀.04 O_(x).

EXAMPLES 19 TO 20

The catalyst of Example 2 was calcined in the absence of air flow for 3hours at 400° C. and subsequently was reacted with methacrolein at 343°C. A second run was made at 377° C.

EXAMPLE 21

The catalyst of Example 2 was reacted in the same manner as in Example19, except it was calcined in air and subsequently was reacted withmethacrolein at 313° C.

These experimental results are found in Table II.

                  TABLE II                                                        ______________________________________                                        EFFECT OF PROPER CALCINATION AND REACTION                                     TEMPERATURE USING THE CATALYST                                                Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.04 O.sub.x                           Results, %                                                                          Single             Total                                    Example                                                                              Calcination                                                                              Pass Yield                                                                              Selectivity                                                                            Conversion                               ______________________________________                                        19     without air                                                                               7.9      60       13.1                                     20     without air                                                                              14.1      80       17.5                                     21     in air     66.7      73       91.5                                     ______________________________________                                    

Thus, the reaction temperature coupled with proper calcination of thecatalysts are critical in obtaining desirable yields of methacrylic acidby the process of the invention.

EXAMPLES 22 TO 28

Preparation of Methacrylic Acid Using Catalysts of the Invention:

EXAMPLE 22

A catalyst of the formula 20% Mo₁₂ P₁.32 Bi₀.5 Cu₀.25 Cl₀.07 O_(f) + 80%Alundum was prepared as follows:

A solution consisting of 105.9 grams of ammonium heptamolybdate, (NH₄)₆Mo₇ O₂₄.4H₂ O, (0.6 mole M), and 500 mls. of distilled water was boiledwith stirring. To this solution was added 7.9 grams of bismuth chloride,BiCl₃ (0.025 mole Bi) as a solution in 15 mls. of concentratedhydrochloric acid; to this solution was added 2.5 grams of copperacetate (0.0125 mole Cu), 7.7 grams of phosphoric acid (0.066 mole P),and 2.5 grams of hydrazine hydrate. The mixture was boiled to drynessand dried overnight at 110° C. This material was ground and screened toless than 80 mesh size and then coated onto Norton SA 5223 1/8 inchAlundum balls by taking 50 grams of Alundum, wetting the Alundum with1.8 grams of water and adding 16.7 grams of the powdered material infive equal portions. During and after each addition, the Alundum wasrolled in a glass jar. The resulting product was then dried in an ovenat 110°-120° C. overnight.

EXAMPLE 23 20%Mo₁₂ P₁.32 Bi₀.5 Cu₀.25 Cl₀.16 O_(f) + 80% Alundum

This catalyst was prepared in the same manner described above, exceptthat hydrazine hydrate was deleted.

EXAMPLE 24 15%Mo₁₂ P₁.32 Bi₀.5 Cu₀.25 Cl₀.06 O_(f) + 85% Alundum

The active catalytic material was prepared in the same manner describedin Example 1, Part A, ground and screened to less than 50 mesh; and thencoated onto Norton 5223 1/8 inch Alundum balls by taking 25 grams ofAlundum, wetting the Alundum with 1.3 grams of water and adding 4.17grams of the powdered catalytic material in a single portion. Thisresulting material was then dried in an oven at 125° C. overnight.

EXAMPLE 25 25%Mo₁₂ P₁.32 Bi₀.5 Cu₀.75 Cl₀.06 O_(f) + 75% Alundum

This catalyst was prepared in the same manner described in Example 24,except that the Alundum was wetted with 1.8 grams of water of 6.94 gramsof the powdered catalytic material were added in two equal portions.

EXAMPLE 26 40%Mo₁₂ P₁.32 Bi₀.5 Cu₀.25 Cl₀.06 O_(f) + 60% Alundum

This catalyst was prepared in the same manner described in Example 24,except the Alundum was wetted with 2.1 grams of water and 11.1 grams ofthe powdered catalytic material were added in three equal portions. Thecatalyst was then dried in an oven at 110° C overnight.

EXAMPLE 27 25%Mo₁₂ P₁.32 Bi₀.5 Cu₀.25 Cl₀.06 O_(x) + 75% Alundum

The active catalytic material was prepared in the same manner describedin Example 1, Part B; ground and screened to less than 50 mesh; and thencoated onto 10/30 mesh particles of Norton SA 5223 Alundum by taking 50grams of the 10/30 mesh Alundum, wetting the Alundum with 4 grams ofwater and adding 16.7 grams of the powdered catalytic material inthree-3 grams portions and one-6.7 grams portion. This resultingmaterial was dried at 110°-120° C.

EXAMPLE 28 35%Mo₁₂ P₁.32 Bi₀.5 Cu₀.25 Cl₀.06 O_(x) + 65% Alundum

This catalyst was prepared in the same manner described in Example 27,except the Alundum was wetted with 2.2 grams of water and 26.9 grams ofless than 80 mesh powdered catalytic material were added in 4 equalportions.

EXAMPLES 29 TO 48

Preparation of methacrylic acid using various coated catalysts of theinvention.

The catalysts were prepared in the same manner shown above using theappropriate ratios of ingredients. The resulting products were calcinedfor three hours at 400° C. in air to form the active catalysts whichconsisted of the Alundum support with a continuous, strongly adheringcoating of the active catalyst.

Each catalyst prepared in Examples 22 to 28 was charged to the reactordescribed in Examples 10 to 18. The reactor was heated to reactiontemperature under a flow of air and then a feed ratio ofmethacrolein/air/steam/nitrogen of 1/5.3/5.6/4.6 was fed over thecatalyst at an apparent contact time of 2.5 to 2.7 seconds. The reactionconditions and results of the experiments are shown in TABLE III.

                                      TABLE III                                   __________________________________________________________________________    PERFORMANCE OF COATED CATALYSTS IN THE                                        PREPARATION OF METHACRYLIC ACID                                                                                     Results, %                                                              Reaction                                                                            Methacrylic                                                                          Acetic                                                                            Total                        Example                                                                              Catalyst                 Temp° C                                                                      Acid   Acid                                                                              Conversion                                                                           Selectivity           __________________________________________________________________________    29     20%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.07 O.sub.f            + 80% Alundum            302   40.6   1.5 48.0   84.0                  reduced                                                                       30     20%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.07 O.sub.f            + 80% Alundum            327   64.0   3.6 78.0   82.0                  31     20%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.07 O.sub.f            +  80% Alundum           337   68.3   4.6 86.7   79.0                  32     20%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.07 O.sub.f            + 80% Alundum            352   68.0   5.9 90.8   75.0                  33     20%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.16 O.sub.f            + 80% Alundum            302   38.0   1.3 43.0   87.0                  unreduced                                                                     34     20%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.16 O.sub.f            + 80% Alundum            327   60.0   2.7 70.0   85.0                  35     20%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.16 O.sub.f            + 80% Alundum            338   66.0   3.5 79.9   83.0                  36     20%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.16 O.sub.f            + 80% Alundum            352   69.4   4.5 87.0   80.0                  37     25%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f            + 75% Alundum            327   30.8   1.5 37.0   83.0                  Ex. 1,                                                                        Part A                                                                        38     25%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f            + 75% Alundum            351   48.3   2.8 60.0   80.0                  39     25%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f            + 75% Alundum            377   55.7   5.4 77.4   72.0                  40     15%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f            + 85% Alundum            315   49.5   3.9 64.0   78.0                  Ex. 1,                                                                        Part A                                                                        41     15%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f            + 85% Alundum            351   36.5   1.9 43.0   84.0                  42     40%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f            + 60% Alundum            325   49.2   2.6 60.4   81.0                  43     40%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f            + 60% Alundum            349   63.2   5.8 85.3   74.0                  44     25%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f            + 75% Alundum            315   60.9   1.7 68.6   89.0                  Ex. 1,                                                                        Part B                                                                        45     25%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f            + 75% Alundum            343   64.0   5.6 90.0   71.0                  46     25%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f            + 75% Alundum            365   63.2   4.6 89.0   71.0                  47     35%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 CU.sub.0.25 Cl.sub.0.06 O.sub.f            + 65% Alumdum            341   63.0   4.8 78.0   80.0                  Ex. 1,                                                                        Pat B                                                                         48     35%Mo.sub.12 P.sub.1.32 Bi.sub.0.5 Cu.sub.0.25 Cl.sub.0.06 O.sub.f            + 65% Alundum            348   60.8   8.1 85.0   71.5                  __________________________________________________________________________

EXAMPLE 49

In the same manner described in Examples 10 to 18, acrylic acid wasprepared from acrolein using the catalyst of Example 1, Part A, Mo₁₂P₁.32 Bi₀.5 Cu₀.25 Cl₀.06 O_(f). The results of this experiment revealeda 75.1% per pass conversion to acrylic acid, 85.3% total conversion, and88.0% selectivity at a reaction temperature of 317° C.

We claim:
 1. In a process for the preparation of acrylic acid ormethacrylic acid by the oxidation of acrolein or methacrolein,respectively, with molecular oxygen in the vapor phase at a reactiontemperature of about 200° C to about 500° C in the presence of an oxidecatalyst, and optionally in the presence of steam, the improvementcomprisingusing as the catalyst a catalyst of the formula

    Mo.sub.12 P.sub.a Bi.sub.b Cu.sub.c M.sub.d X.sub.e O.sub.f

wherein M is at least one element selected from the group consisting ofiron, chromium, nickel, manganese, tellurium, palladium, antimony,rhodium, or mixtures thereof; X is a halogen selected from the groupconsisting of chlorine, bromine, or iodine; and wherein a, b, and c arenumbers from 0.001 to 10; d is from 0 to 10; e is from 0 to 5; f is apositive number of oxygens required to satisfy the valence states of theother elements present.
 2. The process of claim 1 wherein the catalystis calcined at a temperature of 325°-450° C in air.
 3. The process ofclaim 1 wherein the reaction temperature is 250°-370° C.
 4. The processof claim 1 wherein d is zero.
 5. The process of claim 1 wherein a, b,and c are numbers from 0.01 to 5 and e is from 0 to 1.0.
 6. The processof claim 1 wherein a is 1 to 1.5.
 7. The process of claim 1 wherein b is0.1 to 0.5.
 8. The process of claim 1 wherein c is 0.1 to 1.0.
 9. In aprocess for the preparation of acrylic acid or methacrylic acid by theoxidation of acrolein or methacrolein, respectively, with molecularoxygen in the vapor phase at a reaction temperature of about 200° C toabout 500° C in the presence of an oxide catalyst, and optionally in thepresence of steam, the improvement comprisingusing as the catalyst acatalyst of the formula

    Mo.sub.12 P.sub.a Bi.sub.b Cu.sub.c M.sub.d X.sub.e O.sub.f

wherein M is at least one element selected from the group consisting ofiron, chromium, nickel, manganese, tellurium, palladium, antimony andrhodium; X is a halogen selected from the group consisting of chlorine,bromine or iodine; and wherein a, b and c are numbers from 0.001-10; dis from 0-10; e is from 0.01-0.2; and f is a positive number of oxygensrequired to satisfy the valence states of the other elements present.10. In a process for the preparation of acrylic acid or methacrylic acidby the oxidation of acrolein or methacrolein, respectively, withmolecular oxygen in the vapor phase at a reaction temperature of about200° C to about 500° C in the presence of an oxide catalyst, andoptionally in the presence of steam, the improvement comprisingusing asthe catalyst a catalyst of the formula

    Mo.sub.12 P.sub.a Bi.sub.b Cu.sub.c M.sub.d X.sub.e O.sub.f

wherein M is at least one element selected from the group consisting ofiron, chromium, nickel, manganese, tellurium, palladium, antimony andrhodium; X is a halogen selected from the group consisting of chlorine,bromine or iodine; and wherein a, b and c are numbers from 0.001-10; dis from 0-10; e is 0.01-0.5; and f is a positive number of oxygensrequired to satisfy the valence states of the other elements present.11. The process of claim 10 wherein M is at least one element selectedfrom the group consisting of Fe, Cr, and Ni.
 12. The process of claim 10wherein X is chlorine.
 13. The process of claim 10 wherein the catalystemployed is Mo₁₂ Bi₀.5 P₁.32 Cu₀.25 Cl₀.06 O_(f).
 14. The process ofclaim 1 wherein the catalyst is coated on an inert support.
 15. Theprocess of claim 14 wherein the catalyst consists essentially of aninert support material having a diameter of at least 20 microns and anouter surface, and a continuous coating of said active catalyst stronglyadhering to the outer surface of said support.
 16. The process of claim15 wherein the active catalyst is about 10 to about 100 percent byweight of the inert support.
 17. The process of claim 15 wherein thesupport is selected from the group consisting of silica, alumina,Alundum, alumina-silica, silicon carbide, titania and zirconia.
 18. Theprocess of claim 15 wherein the particle size of the inert support is0.2 cm. to 2 cm.
 19. The process of claim 1 wherein methacrolein isreacted.
 20. The process of claim 1 wherein acrolein is reacted.